Heart stimulator housing having a tubular connector

ABSTRACT

A metallic pulse generator housing has a tubular connector which receives a proximal lead end plug, the connector being located inside the housing and having a closed end within the housing and an open end welded or bonded to an opening in a wall of the housing. The connector is formed by a metallic barrel which is weldable or bondable to the metallic housing, the barrel being a structurally unitary tube member with a cavity containing electrical contacts for contacting contact surfaces on the lead end plug. At least one insulating substrate, on which the contacts are carried, is arranged in or on a region of a barrel wall which defines the cavity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a housing and an electrode leadadapter for a heart stimulator.

2. Description of the Prior Art

An implantable pacemaker (pacer) is a system composed of a pulsegenerator and the pacing lead(s) connected thereto. At the proximal endof each pacing lead is a male plug (terminal pin) which is connected tothe pulse generator, and at the distal end of the lead there is (atleast) one electrode adapted to be implanted in (or in the vicinity of)a patient's heart. The pulse generator normally has a housing (“case” or“can”), which contains a battery and electronic circuitry, and aconnector (“header”). The connector is a receptacle into which saidpacing lead(s) is (are) inserted.

The internal parts of the pacer must be well protected, especiallyagainst body fluids, for a long time period. This places strictrequirements on all entries into the interior of the housing, especiallyon the lead connection to the housing. It should also be possible todisconnect the pulse generator from the implanted lead(s), e.g. forreplacement or servicing of the generator. The connective parts of thepulse generator and the lead(s) have largely been standardized toinclude in practice a relatively deep female socket having internalcontact surfaces, while the male plug (at the proximal end of each lead)has corresponding external contact surfaces.

Conventionally the connective pulse generator housing part containingthe female socket is made of a transparent material, usually a medicalgrade epoxy resin, which is molded onto the housing and onto contactsprotruding from the housing. The lead's male plug is normally locked inthe connector receptacle by means of a set-screw or some other fasteningmeans. However, the positioning and alignment of the contact surfacesand of the fastening means or metallic threads for the set-screw, priorto the molding of the connective part, is very complicated, and thedelay in the manufacturing process incurred by the curing of the epoxyis considerable.

Thus, it would be desirable that such a molding procedure could bedispensed with.

It has been considered that a possibility of avoiding these problemsmight be to design a pulse generator which is provided with a femalesocket located inside its metal housing, however, such an integratedsocket, sometimes called a “black hole”, is presently not used.

U.S. Pat. Nos. 4,262,982, 4,934,366 and 5,324,311 describe interiorsockets or blind holes in pacemaker housings. In all cases the interiorsocket has a tubular member formed of a number ofjoined sections ofdifferent materials, e.g. metal and insulating ceramics. A metallic endsection of the tubular member can be welded or bonded to an opening inthe pacemaker housing by means of an exterior flange on the end section.However, the use of sections of different materials in the tubularmember makes the assembly procedure more complicated and demandingregarding precision and durability of the components. The integrity ofthe interior of the housing also must be guaranteed during a very longperiod of implantation.

U.S. Pat. No. 5,007,864 discloses a lead-to-pacemaker adapter whichallows the use of a smaller diameter terminal electrode lead assemblythan that for which the pacemaker was designed. The adapter permitsdirect electrical connection from the terminal pin electrode (at theproximal lead end portion) to the pacemaker connector block and itsterminal set screw, without any intermediate connecting elements.

The adapter is tubular and includes a cylindrical body which tapers atits rear open end to an extension. At its forward closed end the adapterhas an end face from which an electrically conductive half-round tubeextends outwardly. On its underside the adapter has a retaining bumpprovided for latching the adapter in place within a receptacle cavity inthe pacemaker's head portion. Near the outer opening of the receptaclecavity there is a small hole along the bottom side thereof. When theadapter is inserted in place within the receptacle cavity said retainingbump engages within said small hole.

When the terminal pin electrode at the proximal lead end portion hasbeen inserted into the adapter, the pin electrode will be positioned inthe channel-shaped half-round tube at the forward end of the adapter. Asocket recess set screw, which is threaded into the connector block, isbrought into contact and locking engagement with said pin electrode,thereby retaining the lead assembly in firm mechanical and electricalcoupling to the pacemaker.

U.S. Pat. No. 4.583.543 discloses an upsizing adapter for electricallyand mechanically coupling a small size terminal electrode assembly(which is mounted at the proximal end of a pacing lead) to a large sizeterminal electrode assembly socket in a pacemaker. The adapter isadapted to be inserted into the electrode assembly socket in thepacemaker, and the electrode assembly at the proximal end of the pacinglead is inserted into a socket in the adapter. Thus, the smallerterminal electrode assembly at the lead's proximal end is received andheld in a larger size socket in the pacemaker by means of the adapter.The adapter with the pacing lead electrode assembly inserted therein isretained in the pacemaker socket by means of an Allen set screw in aconnector block within an upper body portion of the pacemaker. A pointedtip of the set screw forces a side wall portion of the adapter's forwardend tube (enclosing the lead's terminal pin electrode) into contact withthe lead's terminal pin electrode. In this way, an electrical andmechanical connection is provided between the pin electrode and theconnector block.

SUMMARY OF THE INVENTION

A primary object of the invention is to provide a tubular connector fora pulse generator housing that is suitable for so called black holes.

A further object is provide a connector which produces a mechanicallylocking, electrical connection of a proximal lead end portion to thelead connection unit in a pacemaker or some other type of pulsegenerator.

Another object of the invention is to design a tubular connector, aswell as an adapter suitable for that type of connector, whichfacilitates the connection of an undersized proximal lead end electrodeassembly to the receiving cavity of the lead connection unit of a heartstimulator.

A still further object is to provide a connector including a tubular,male plug receiving member or barrel being designed to be optimized froma manufacturing as well as a strength-of-material standpoint.

The above objects are achieved in accordance with the principles of thepresent invention in a metallic pulse generator housing having a tubularconnector adapted to receive a proximal lead end plug, the connectorbeing located inside the housing and having a closed end within thehousing and an open end that is welded or bonded to an opening in a wallof the housing. The connector is formed by a metallic barrel which isweldable or bondable to the metallic housing, and has a structurallyunitary tube member with a cavity containing electrical contacts forcontacting contact surfaces on the lead end plug. At least oneinsulating substrate is arranged in or on a region of the barrel wallwhich defines the cavity. The substrate has contacts on a surfacethereof facing into said cavity.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a partly assembled tubular connectoraccording to the invention.

FIG. 2 shows (on a larger scale) a bottom view of the connector in FIG.1.

FIG. 3 shows an end view of the connector in FIG. 2.

FIG. 4 shows a longitudinal section through the connector, at planeIV—IV in FIG. 3.

FIG. 5 shows an end view of the inventive connector in fully assembledstate.

FIG. 6 shows a longitudinal section through the connector in FIG. 5. atplane VI—VI thereof.

FIG. 7 shows an end view of the barrel of the tubular connector in FIGS.1-6.

FIG. 8 shows a longitudinal section through the barrel in FIG. 7, atplane VIII—VIII thereof.

FIG. 9 shows a bottom view of the adapter of the tubular connector inFIGS. 1-6.

FIG. 10 shows a side view of the adapter in FIG. 9.

FIG. 11 and FIG. 12 show end views of the right and left ends,respectively, of the adapter in FIG. 9.

FIG. 13 shows a longitudinal section through the adapter in FIG. 11, atplane XIII—XIII thereof.

FIG. 14 shows (on a larger scale) a side view of the substrate slab ofthe connector in FIG. 4.

FIG. 15 shows a cutaway side view of a pulse generator with a tubularconnector barrel mounted in the upper part of the pulse generatorhousing.

FIG. 16 shows a partially cutaway side view of a pulse generator with atubular connector barrel included in a specific receptacle part (header)of the generator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of a metallic housing with tubular connectoraccording to the invention will now be described with reference to FIGS.1-6 and the three major components thereof are depicted separately inFIGS. 7-8, 9-13 and 14, respectively.

In FIGS. 1, 2, 4 and 6 a tubular connector 2 is shown in a partlyassembled state. The connector, which is adapted to form part of a leadconnection unit 100 of a heart stimulator or pulse generatorschematically shown in FIG. 15, has a metallic barrel 4 with a cavity 6having an entrance opening 8 at its rear end (right end in FIGS. 4 and8). In a thickened side wall portion 10 of the barrel 4 there is formedan elongated, longitudinal through opening 12 between the cavity 6 andthe outside of the barrel. A rectangular slab or substrate 14 of ceramicmaterial is sealingly fastened in opening 12, e.g. by brazing solder 16.On its narrow longitudinal top side 18 the slab 14 is provided with twospaced apart contacts 20, 22 with convex surfaces that are metallizedwith e.g. gold. These contacts are individually electrically connectedto a pair of external pads 24, 26 on a lateral surface 28 of the slab,see FIGS. 1 and 14.

The substrate 14 may, however, alternatively be an integral part of thesubstrate carrying the internal electronics of the pacer, this substratethus extending into the opening 12 and being sealingly fastened thereto.In the case of a pacer with two connectors, the connectors could belocated on opposite sides of the electronics substrate with thesubstrate extending into the respective openings 12. In both cases,separate conducting means connecting the internal electronics with thebarrel would not be necessary. This design of course could be usedregardless of whether the embodiment utilizing the adaptor part is usedor an embodiment is used in which the means connecting the substratewith the male connector are permanently mounted in the barrel.

As shown in FIGS. 1,2 and 4 a tubular adapter 30 is insertable andsealingly lockable in the barrel cavity 6. This adapter, whichconstitutes a casing with a central bore 32, is made of an elastic,electrically insulating material, e.g. a semi-soft elastomer, which maybe transparent to allow easy visual supervision of the position of aproximal lead end portion 34 which is inserted into the adapter bore 32.The rear end portion of the adapter is axially split open into twohalf-shells 36, 38. Each half-shell has an outward flange 40 at its rearend. As visible in FIGS. 1-3 and 9-13 one half-shell 38 is elasticallyand flexibly connected with the rest of the adapter by a transitionportion 42.

The half-shells 36, 38 are provided, on the insides thereof, with alocking mechanism adapted to lock the proximal lead end portion 34 inits fully inserted position in adapter bore 32 when also the adapteritself has been fully inserted into the barrel cavity 6. This lockingmechanism includes circumferential engagement elements, e.g. ribs 44,which are brought into engagement with the lead end portion 34 when thehalf-shell 38 is turned down (from its angular position shown in FIGS.1-3) to its axial engagement position obtained by fully inserting theadapter 30 into barrel cavity 6, as shown in FIG. 6.

Furthermore, to space apart and mutually seal the electrical polesurfaces 46, 48 on the outside of the adapter tube or casing from eachother in barrel cavity 6, the adapter is provided, on the outsidethereof, with axially spaced apart circumferential grooves 50, 52, 54(see FIGS. 9, 10, 13) adapted to accommodate 0-ring type sealingelements 50 a, 52 a, 54 a (see FIGS. 4 and 6).

When the adapter 30, with the lead end portion 34 fully inserted therein(as in FIG. 4), has been axially fully inserted in barrel cavity 6 (asin FIG. 6), the adapter is positively locked in position therein bybeing turned clockwise 90°, so that slots 56, 58 (which contain the polesurfaces 46, 48) will slide onto the convex contacts 20, 22 on slab 14.Thereby the adapter will become mechanically locked in position incavity 6, and the metal parts (e.g. thin metal leafs carrying polesurfaces 46, 48) molded in the elastomeric adapter will becomeelectrically connected to the convex or spherical, metallic contacts 20,22 on the ceramic material slab 14.

To facilitate the 90° turning of the adapter, the flanges 40 of the twohalf-shells 36, 38 are provided, at the edges thereof, with a suitablenumber of notches 60 adapted to be engageable by means of an external,simple, adapter turning tool (not shown on the drawings). To turn theadapter this tool is merely folded around the lead end portion 34 andfit into the notches 60 in the adapter flanges 40, whereupon the adaptercan be turned 90° to its definite locking position.

The tubular connector 2 is adapted to form part of a lead connectionunit of a heart stimulator or pacemaker. Such a unit can be positionedin a header or specific receptacle part of a pacemaker, or in a “blackhole” cavity provided in the actual pacemaker housing or can. Tofacilitate the installation of the tubular connector according to theinvention in a header or such black hole, the barrel 4 preferably isprovided with a circumferential flange 62 in the region of its entranceopening 8. By means of this flange the adapter can be attached easily tothe pacemaker can, e.g. by laser welding.

In FIG. 15 there is shown a pacemaker housing or can 64 containing aconnector barrel 4, electrical circuits 66 and a battery 68. In thiscase the barrel 4 is mounted in an opening 70 in a side wall portion 72of the upper part of the housing 64. The barrel 4 is attached to thewall portion 72 by means of the circumferential flange 62 which is laserwelded to the wall portion. The preferably cylindrical cavity 6 withinthe barrel 4 is adapted to receive and support an adapter 30 (having aproximal lead end portion inserted therein), in the way shown in FIG. 6.Thus, the socket configuration shown in FIG. 15 is of the “black hole”type. A substrate 14, which is made of an electrically insulatingmaterial and provided with contacts 20. 22, is sealingly fastened in alongitudinal through opening in a thickened wall portion 10 of thebarrel 4.

In FIG. 16 there is shown a more conventional pacemaker having a housingor case 74 with a specific receptacle part or header 76 attachedthereto. This header 76 may e.g. be an epoxy resin body 78 molded on aplanar top surface 80 of case 74. The tubular connector barrel 4 may beembedded in epoxy body 78 from the very molding thereof or may beinserted afterwards in a cylindrical cavity formed in the molded body.

In the preferred embodiment described above, the cavity having theinsulating substrate has been illustrated as being located laterally inthe envelope surface of the tubular connector (which in the preferredembodiment is cylindrical). It should be noted that the insulatingsubstrate of course could be located in the end of the connector forinstance forming a plug brazed or soldered into the end of theconnector. The inner side of the plug then could carry the spaced-apartcontact surfaces, which for instance could be arranged concentrically onsaid inner surface and which would be in electrical connection with theexterior of the tubular connector. The tubular adapter would be providedwith corresponding exterior contacts on the outer end surface being inelectrical connection with the contacts on the inside of the adapter. Inother respects the design would be similar to the design described inthe preferred embodiments with lateral slots and lugs forming a bayonetjoint between the adapter and the connector.

Although modifications and changes may be suggested by those skilled inthe art, it is the intention of the inventor to embody within the patentwarranted hereon all changes and modifications as reasonably andproperly come within the scope of his contribution to the art.

What is claimed is:
 1. In a metallic pulse generator housing having atubular connector adapted to receive a proximal end plug of an electrodelead, said connector being disposed inside said housing and having aclosed end within said housing and an open end attached to an opening ina wall of said housing, the improvement of said connector comprising: ametallic barrel attached to said metalic housing and formed by astructurally unitary tube member having a cavity containing electricalcontacts adapted for respectively contacting contact surfaces on saidproximal end plug, said metallic barrel having a barrel wall definingsaid cavity; and an insulating substrate, carrying said electricalcontacts, disposed at a portion of said barrel wall.
 2. The improvementof claim 1 wherein said substrate is disposed in said barrel wall. 3.The improvement of claim 1 wherein said substrate is disposed on saidbarrel wall.
 4. The improvement of claim 1 wherein said cavity has anentrance opening at said open end of said connector and wherein saidbarrel wall comprises a side with a through opening therein providingcommunication between said cavity and an exterior of aid barrel, andwherein said improvement further comprises: a tubular adapter insertableinto and sealingly lockable in said cavity, said adapter being composedof electrically insulating material and having a rear end portion havinga locking mechanism adapted to lock said proximal end plug within saidadapter when said proximal end plug is inserted into said adapter andwhen said adapter is fully inserted in said barrel cavity; and whereinsaid substrate is sealingly fastened in said opening in said side wallof said barrel and wherein said contacts carried by said substrate matewith contact elements at an exterior of said adapter when said adapteris fully inserted in said cavity.
 5. The improvement of claim 4 whereinsaid through opening is an elongated, longitudinal opening in athickened side wall of said barrel, and wherein said substrate is aunitary substrate element at least partially disposed in saidlongitudinal opening and positively fixed in said opening.
 6. Theimprovement of claim 5 wherein said substrate is a slab of ceramicmaterial having a narrow longitudinal al side with two spaced-apartcontacts respectively having convex surfaces adapted to contact withsaid mating contact elements at said surface of said adapter, saidcontacts on said slab being individually electrically connected with adsdisposed at a surface of said slab at said exterior of said barrel. 7.The improvement of claim 4 wherein said through opening comprises atleast two spaced-apart openings a thickened side wall of said barrel,and wherein said substrate comprises respective substrate elements ineach of said spaced-apart openings, each substrate element being atleast partially disposed in the respective opening and positively fixedtherein.
 8. The improvement of claim 4 wherein said adapter has a casingwith a central bore with an entrance opening adapted for insertion ofsaid proximal end plug, and wherein said rear end portion of saidadapter is axially split into two half-shells, at least one of saidhalf-shells being elastically connected with a remainder of said adapterand having an outward flange at said rear end.
 9. The improvement ofclaim 8 wherein each of said half-shells has a shell rear end, andwherein each of said half-shells has an outward flange at its shell rearend, each flange having an edge with at least one notch therein adaptedfor engagement with an externally applicable adapter turning tool. 10.The improvement of claim 8 wherein said adapter, on an inside of each ofsaid half-shells, has circumferential engagement elements adapted forengagement with said proximal end plug when said two half-shells areclosed and locked around said proximal end plug.
 11. The improvement ofclaim 8 wherein at least one of said half-shells subtends an acute anglewith a longitudinal axis of said adapter when said rear end portion ofsaid adapter is free and not inserted into said cavity of said barrel.12. The improvement of claim 4 wherein said adapter is comprised ofelastic material.
 13. The improvement of claim 12 wherein said adapteris comprised of a semi-soft elastomer.
 14. The improvement of claim 12wherein said adapter is comprised of transparent elastic material. 15.The improvement of claim 4 wherein said adapter has an exterior havingaxially spaced circumferential grooves with respective sealing elementstherein.